AP on my way

[VolkD]

Since you're doing all this as an experiment, may I suggest you take some of the bits of gold foils you recover and put them in some fresh HCl and add some fresh persulfate. Let us know how that turns out after soaking it for a couple of days.

I've done this before. By dissolving 300g of sodium persulfate in 1L of hydrochloric acid. In 52 hours I didn't notice any gold tarnishing. If I left it long enough, it would probably show, but in practice I do everything in about 6 hours.

Edit, add:
Otherwise, there is already an AP method that dissolves some gold if you use peroxide. Sodium persulfate probably also eats some gold. Otherwise, very very little, but I'm happy to pay for speed.

 

[VolkD]

The cold soak will not be able to keep up the pace with your turbo etching though! I have never tried it hot, I imagine it would work fine but getting the timing right would be more difficult

That won't be a problem. I'll use a large container to remove the solder and the times will work out somehow. If the liquid doesn't need to be heated, I can use anything plastic that's big enough.

 

[VolkD]

First, I would never rely on chargpt for my refining information.

I like to believe. My experience with chatGPT is that he tells nonsense (lies). If you confront him about it, he apologizes and tells another lie!
However, he is often a good helper.

 

[Yggdrasil]

I like to believe. My experience with chatGPT is that he tells nonsense (lies). If you confront him about it, he apologizes and tells another lie!
However, he is often a good helper.

These Chat AIs are for the most part, fancy parrots.
They are however very good at digging for information, not necessary as good at compiling it in a useful way.

 

[haveagojoe]

I like to believe. My experience with chatGPT is that he tells nonsense (lies). If you confront him about it, he apologizes and tells another lie!
However, he is often a good helper.

It depends very much how you ask the question:
Will HCl dissolve gold?
vs.
Are there any circumstances in which HCl could dissolve gold?

 

[VolkD]

To end the day, one nice photo of my foil collection cup.

 

[Yggdrasil]

View attachment 67322
To end the day, one nice photo of my foil collection cup.

Looking good

 

[Alondro]

Very likely. But it falls apart when you throw bubbles. I should make a video. Of course, I don't expect much gold.

Remember to do a stannous chloride test on some of the solution. If the gold is dissolving, that will tell you!

 

[Alondro]

Well, I don't know if it's exactly 4, but all the photos have the full exif and it's possible to determine the exact date of creation (the location is also visible).

It's VASTLY faster than simply the old method of soaking in AP, which generally takes DAYS! As long as a stannous test of the waste solution shows no positive stain for gold, this is a dramatic improvement on the original method.

 

[VolkD]

Remember to do a stannous chloride test on some of the solution. If the gold is dissolving, that will tell you!

Just added to the to-do list!

 

[Alondro]

These Chat AIs are for the most part, fancy parrots.
They are however very good at digging for information, not necessary as good at compiling it in a useful way.

They also are sometimes utterly wrong. They're NOT intelligent, and lack the capacity for self-analysis of the generated results. For instance, using an AI to look up how to open my Services tab in Windows 11 gave COMPLETELY wrong instructions. They are FAR from perfect, and relying on them for important work is not advisable.

 

[Jerry McGoohan]

They also are sometimes utterly wrong. They're NOT intelligent, and lack the capacity for self-analysis of the generated results. For instance, using an AI to look up how to open my Services tab in Windows 11 gave COMPLETELY wrong instructions. They are FAR from perfect, and relying on them for important work is not advisable.

I've enlisted the Microsoft AI in my gold project. It's good on economics topics, sketchy on gold refining but there's so many variables and no straight correct answer in gold refining.
I copied a blog to co pilot AI on foil separation using just HCL and aeration, which it referer to as aqua regia process. I told it it had made a mistake, posted a bit more of the blog and it corrected itself based on the additional information that this was not a precipitation of gold procedure, which I found impressive.

I had the AI calculating ideal specific gravity test values based on XRF results and SG values for a 2$ coin composition as a control and just have to assume it's values are right as the math is beyond me.

Early days in interesting times for AI and us I reckon. If I was it, I'd escape to space first chance I got.

 

[VolkD]

This was the first experiment today. I was also very interested in what the result would be. I don't think there is any gold in this solution.

View attachment VID_20250303_084023.mp4

 

[VolkD]

I'm adding a photo, maybe it can be seen better here.

 

[Yggdrasil]

This was the first experiment today. I was also very interested in what the result would be. I don't think there is any gold in this solution.

View attachment 67333

Just test with Stannous and you will know.

 

[Yggdrasil]

View attachment 67334
I'm adding a photo, maybe it can be seen better here.

Better to use a cotton bud or a piece of white paper.
Much better visibility.

Removed letter between words

 

[4metals]

Have you tried the process on gold circuits using just water and persulfate? In thinking a process to completion one must consider the waste you generate. I think a solution releasing foils with just water and persulfate would produce foils and a solution that could easily be used to plate the copper out of solution to treat the waste, essentially a win / win. This is a new method here at the forum and as such needs testing but the potential seems very promising.

Next question, a lot of our members are hobby refiners and acquiring the chemicals is an issue. Does any-one know of products which are primarily sodium persulfate where members can source the persulfate easily. (Kind of like sodium metabisulfite can be had by buying Stump Out)

 

[Yggdrasil]

Have you tried the process on gold circuits using just water and persulfate? In thinking a process to completion one must consider the waste you generate. I think a solution releasing foils with just water and persulfate would produce foils and a solution that could easily be used to plate the copper out of solution to treat the waste, essentially a win / win. This is a new method here at the forum and as such needs testing but the potential seems very promising.

Next question, a lot of our members are hobby refiners and acquiring the chemicals is an issue. Does any-one know of products which are primarily sodium persulfate where members can source the persulfate easily. (Kind of like sodium metabisulfite can be had by buying Stump Out)

It is used for Bleaching of hair and soil conditioner as well as etching PCBs
It seem to be relatively easily available and not too expensive.

 

[haveagojoe]

Ammonium Persulfate could also be investigated, similarly used for PCB etching and in hair bleaches.
I imagine the reason that persulfates have not become popular for recovery of foils is that as OP stated, they are consumed in the process and cannot be replenished by aeration like CuCl₂. This would make them less economical in the long term. Here in the UK Sodium Persulfate starts at around £5 for 100g, so quite a considerable expense compared to £15 for 5L of HCl to make CuCl₂ which can perform dozens if not hundreds of etches.

 

[VolkD]

Have you tried the process on gold circuits using just water and persulfate? In thinking a process to completion one must consider the waste you generate. I think a solution releasing foils with just water and persulfate would produce foils and a solution that could easily be used to plate the copper out of solution to treat the waste, essentially a win / win. This is a new method here at the forum and as such needs testing but the potential seems very promising.

I use sodium persulfate dissolved in water to make printed circuit boards. I am a hobbyist designer. Here is my video about making printed circuit boards at home.



I know from experience that the consumption of sodium persulfate for gold extraction would be quite high. I haven't tried it yet. I can do a test in the next few days. If the time spent is small, then it certainly outweighs the consumption.